1. Field of the Invention
The present invention relates to a lens barrel equipped with a retreatable optical system that retreats from a position on the optical axis for storage, a camera that includes the lens barrel and an adjustment device that adjusts the lens barrel.
2. Description of Related Art
Japanese Laid Open Patent Publication No. 2003-315861 discloses a retractable lens barrel used in photographing operation executed in a camera. The length of this lens barrel in storage is reduced by allowing some of a plurality of lens groups to move (slide) rotationally around a rotating shaft fixed to the lens barrel so as to retreat along a direction extending perpendicular to the optical axis and storing the other lens groups into the space thus created.
The lens barrels used in photographing operations executed in cameras in the related art include those equipped with optical blur correction devices. A blur correction device detects a vibration to which the optical system has been subjected via an angular speed sensor or the like and reduces the extent of an image blur manifesting on the image forming plane by driving some (blur correction lens group) of a plurality of lens groups within a plane ranging perpendicular to the optical axis based upon the extent of vibration thus detected.
Japanese Laid Open Patent Publication No. 2004-233922 discloses an example of a lens barrel in the related art, which includes a lens group made to retreat away from the optical axis. Decentering may occur in this lens barrel due to inconsistent accuracy in mechanical portions and the like used in the retreating operation, and for this reason, it includes an aligning mechanism that displaces the lens group by shifting it along a direction perpendicular to the optical axis so as to reduce the extent of the decentering.
However, the addition of the aligning mechanism leads to an increase in the number of required parts, resulting in a lens barrel with a more complex structure. The addition of an aligning mechanism becomes particularly problematic in the case of a lens barrel equipped with a blur correction device, since the sufficient installation space for the aligning mechanism needs to be secured in the already tight available space.
According to the first aspect of the invention, a lens barrel comprises: a fixed optical system through which a subject image enters into the lens barrel along with an optical axis; a retreatable blur correction optical system that corrects an image blur by moving within a plane ranging perpendicular to the optical axis in an operating position and that retreats to a storage position from the operating position; a blur correction optical system drive unit that drives the retreatable blur correction optical system within the plane ranging perpendicular to the optical axis; and a correction information recording unit at which reference position correction information is recorded. The correction information indicates a reference position for the retreatable blur correction optical system within the plane ranging perpendicular to the optical axis.
According to the second aspect of the invention, a lens barrel comprises: a fixed optical system though which a subject image enters into the lens barrel along with an optical axis; a blur correction optical system supported so as to be allowed to move within a plane ranging perpendicular to the optical axis to correct an image blur; a retreatable optical system that moves between an operating position and a stored position away from the optical axis, the retreatable optical system being constituted with either an optical system independent of the blur correction optical system or an optical system constituting part of the blur correction optical system; a blur correction optical system drive unit that drives the blur correction optical system within the plane ranging perpendicular to the optical axis; and a correction information recording unit at which reference position correction information is recorded. The correction information indicates a reference position for the blur correction optical system within the plane ranging perpendicular to the optical axis.
The reference position may be a position where the optical axis of the retreatable blur correction optical system or the blur correction optical system substantially coincides with the optical axis of the fixed optical system.
It is preferred that the correction information recording unit provides the correction information to an information acquisition device disposed at a camera body on which the lens barrel is mounted.
A camera according to another aspect of the invention comprises: a fixed optical system through which a subject image enters into a lens barrel along with an optical axis; a retreatable blur correction optical system that corrects an image blur by moving within a plane ranging perpendicular to the optical axis in an operating position and that retreats to a storage position from the operating position; a blur correction optical system drive unit that drives the retreatable blur correction optical system within the plane ranging perpendicular to the optical axis; and a correction information recording unit at which reference position correction information is recorded. The correction information indicates a reference position for the retreatable blur correction optical system within the plane ranging perpendicular to the optical axis.
A camera according to another aspect of the invention comprises: a fixed optical system though which a subject image enters into a lens barrel along with an optical axis; a blur correction optical system supported so as to be allowed to move within a plane ranging perpendicular to the optical axis to correct an image blur; a retreatable optical system that moves between an operating position and a stored position away from the optical axis, the retreatable optical system being constituted with either an optical system independent of the blur correction optical system or an optical system constituting part of the blur correction optical system; a blur correction optical system drive unit that drives the blur correction optical system within the plane ranging perpendicular to the optical axis; and a correction information recording unit at which reference position correction information is recorded. The correction information indicates a reference position for the blur correction optical system within the plane ranging perpendicular to the optical axis.
The camera may further comprises: an imaging device that captures a subject image entering thereto via the lens barrel and outputs an image signal, and the correction information recorded at the correction information recording unit may be generated based upon an output from the imaging device.
According to another aspect of the invention, it is preferred that the retreatable blur correction optical system or the retreatable optical system is configured to swing from the operating position to the storage position around the optical axis as the lens barrel retracts into a camera body.
A lens barrel adjustment device according to the present invention, uses to adjust the lens barrel noted above. The lens barrel adjustment device comprises: an imaging device that captures a subject image formed via the lens barrel and outputs an image signal; a correction information generation unit that evaluates an image signal output from the imaging device while displacing the retreatable blur correction optical system or the blur correction optical system by controlling the blur correction optical system drive unit at the lens barrel and generates reference position correction information indicating a reference position for the retreatable blur correction optical system or the blur correction optical system to be assumed within the plane perpendicular to the optical axis; and a recording unit that records the correction information output by the correction information generation unit into a recording medium disposed within the lens barrel.